Pressure-sensitive adhesive tape for preventing corrosion

Abstract

To provide a pressure-sensitive adhesive tape for preventing corrosion which is scarcely peeled off even under a high temperature environment.SOLUTION: An adhesive tape for preventing corrosion includes an adhesive layer of which the adhesive force maintenance factor at 100°C obtained by the formula is 50% or more. The adhesive force maintenance factor (%)=[adhesive force (N / 25 mm) of the adhesive layer after curing the adhesive tape for preventing corrosion under an environment of 100°C for three days] / [adhesive force (N / 25 mm) of the adhesive layer after curing the adhesive tape for preventing corrosion under an environment of 23°C for one day]×100.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an anticorrosion adhesive tape. [Background technology]

[0002] Anticorrosion paints containing large amounts of zinc are widely used to protect steel and other iron or iron-containing alloys from corrosion. Zinc is a metal with a lower potential than iron and is known to have high corrosion protection due to its sacrificial corrosion protection properties. However, corrosion protection using paint requires a drying process after application, which is time-consuming and reduces work efficiency, for example, when performing localized repairs on civil engineering and construction applications such as bridges. Furthermore, corrosion protection using paint is prone to uneven work. In view of the above circumstances, efforts have been made to improve workability by imparting sacrificial corrosion protection to adhesive tapes, etc. For example, Patent Document 1 discloses an anticorrosion adhesive tape having an adhesive layer, which does not rust in a cyclic corrosion test in accordance with Cycle D of JIS K5600-7-9, and has an adhesive strength of 20 N / 25 mm or more after the cyclic corrosion test. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 191212 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional pressure-sensitive adhesive tapes that have been given corrosion resistance have low heat resistance, and when used to repair pipes that are exposed to high temperatures, for example, they may become prone to peeling over time.

[0005] Therefore, an object of the present invention is to provide an anticorrosion adhesive tape that is difficult to peel off even in a high-temperature environment. [Means for solving the problem]

[0006] As a result of extensive investigations, the present inventors have found that the above-mentioned problems can be solved by setting the adhesive strength retention rate at 100°C of the adhesive layer to a certain level or higher. That is, the present invention provides the following [1] to [9].

[0007] [1] A corrosion-preventive adhesive tape having an adhesive layer, wherein the adhesive layer has an adhesive strength retention rate at 100°C of 50% or more, as calculated by the following formula (1): Adhesive strength retention rate (%) = Adhesive strength (N / 25 mm) of the anticorrosion adhesive tape after curing for 3 days in a 100°C environment / Adhesive strength (N / 25 mm) of the anticorrosion adhesive tape after curing for 1 day in a 23°C environment × 100 (1) [2] The anticorrosion adhesive tape according to [1], wherein the adhesive strength of the adhesive layer after curing the anticorrosion adhesive tape in an environment of 100°C for 3 days is 20 N / 25 mm or more. [3] The anticorrosion adhesive tape according to [1] or [2], wherein the pressure-sensitive adhesive layer has a storage modulus of 140 kPa or more in a 100°C environment. [4] The anticorrosion adhesive tape according to any one of [1] to [3], wherein the adhesive layer is formed from an acrylic adhesive. [5] The anticorrosion adhesive tape according to [4], wherein the acrylic pressure-sensitive adhesive contains structural units derived from (meth)acrylic acid alkyl ester monomers, and the acrylic pressure-sensitive adhesive does not contain a tackifier resin, or the acrylic pressure-sensitive adhesive contains a tackifier resin and the content of the tackifier resin is less than 5 parts by mass per 100 parts by mass of the structural units derived from (meth)acrylic acid alkyl ester monomers. [6] The anticorrosion pressure-sensitive adhesive tape according to any one of [1] to [5], wherein the pressure-sensitive adhesive layer has a gel fraction of 40 to 80 mass %. [7] The anticorrosion adhesive tape according to any one of [1] to [6], wherein the adhesive layer contains zinc. [8] The anticorrosion adhesive tape according to any one of [1] to [7], wherein the adhesive layer contains a conductive material. [9] The anticorrosion adhesive tape according to any one of [1] to [8], wherein the adhesive layer has a thickness of 100 μm or more. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an anticorrosion pressure-sensitive adhesive tape that is resistant to peeling even in a high-temperature environment. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating one embodiment of a pressure-sensitive adhesive tape of the present invention. [Figure 2] 1 is a schematic diagram showing one step of a method for measuring the adhesive strength of an adhesive tape of the present invention. [Figure 3] 1 is a schematic diagram showing one step of a method for measuring the adhesive strength of an adhesive tape of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Anti-corrosion adhesive tape] The anticorrosion adhesive tape of the present invention has an adhesive layer, and the adhesive layer has an adhesive strength retention rate at 100°C (hereinafter simply referred to as "adhesive strength retention rate") of 50% or more, calculated by the following formula (1): Adhesive strength retention rate (%) = Adhesive strength (N / 25 mm) of anti-corrosion adhesive tape after curing for 3 days at 100°C / Adhesive strength (N / 25 mm) of anti-corrosion adhesive tape after curing for 1 day at 23°C × 100 (1)

[0011] If the adhesive strength retention rate is less than 50%, the anticorrosion adhesive tape will be more likely to peel off in a high-temperature environment. From the viewpoint of making the anticorrosion adhesive tape less likely to peel off in a high-temperature environment, the adhesive strength retention rate is preferably 60% or more, more preferably 65% ​​or more, even more preferably 70% or more, and even more preferably 75% or more. The higher the adhesive strength retention rate, the better, but in practice it is, for example, 150% or less, preferably 130% or less. The adhesive strength retention rate can be adjusted by the gel fraction, the adhesive blend ratio, etc., as described below. One example of an embodiment of an adhesive in which the adhesive strength retention rate can be adjusted to 50% or more is an embodiment (hereinafter also referred to as embodiment A) in which the gel fraction is 40% to 80%, the content of the tackifier resin is 0 to 5 mass% based on the total amount of the adhesive layer, the content of the metal in the adhesive layer that is less noble than iron in electric potential is 0.5 to 30 mass% based on the total amount of the adhesive layer, and the content of the conductive material is 0.001 to 10 mass% based on the total amount of the adhesive layer. An example of an embodiment of a pressure-sensitive adhesive in which the adhesive strength retention rate can be adjusted to 50% or more is an embodiment (hereinafter also referred to as embodiment B) in which the gel fraction is 40% to 80%, the content of the tackifier resin is 0 to 5 mass% based on the total amount of the pressure-sensitive adhesive layer, the content of the metal in the pressure-sensitive adhesive layer that is less noble in potential than iron is 0 mass% based on the total amount of the pressure-sensitive adhesive layer, and the content of the conductive material is 0 to 10 mass% based on the total amount of the pressure-sensitive adhesive layer. Examples of the adhesive agent capable of adjusting the adhesive strength retention rate to 50% or more are not limited to those described above, and may be, for example, a combination of the embodiment A and the embodiment B.

[0012] <Adhesive strength after curing for 3 days in a 100°C environment> The anticorrosion adhesive tape of the present invention preferably has an adhesive strength (hereinafter also referred to as "adhesive strength 1") of 20 N / 25 mm or more after curing in a 100°C environment for 3 days, more preferably 25 N / 25 mm or more, and even more preferably 35 N / 25 mm or more. When adhesive strength 1 is equal to or greater than the above lower limit, excellent adhesive strength can be exhibited even in a high-temperature environment. Furthermore, adhesive strength 1 is not particularly limited, but is preferably 70 N / 25 mm or less, more preferably 60 N / 25 mm or less, and even more preferably 55 N / 25 mm or less.

[0013] The adhesive strength 1 can be measured by the following procedure. First, as shown in FIG. 1, a procedure for measuring adhesive strength 1 when sample 10 is a single-sided adhesive tape having a substrate will be described. As shown in Figure 2, sample 10 was removed from the anticorrosion adhesive tape and attached to a SUS plate (SS400) 20, and a 2 kg roller was rolled back and forth on the sample twice. After that, the sample was left to cure in a 100°C environment for 3 days with the substrate attached.

[0014] After curing, Sample 10 is placed in a heating furnace adjusted to 110°C for 5 minutes and baked. After baking, it is placed in a thermostatic chamber adjusted to 100°C and left for 5 minutes, and then a 180° peel test is performed in a 100°C environment at a peel speed of 300 mm / s to determine adhesive strength 1. If anchor failure occurs between the substrate and the adhesive layer during the peel test, the peel test is temporarily stopped. The substrate is then removed, and the exposed adhesive layer is attached to a PET substrate (50 μm) primed with Nippon Shokubai NK350 or the primer-treated side of a similar PET substrate (hereinafter simply referred to as "PET substrate"). With the PET substrate attached, Sample 10 is placed in a heating oven adjusted to 110°C for 5 minutes and baked. After baking, Sample 10 is placed in a thermostatic oven adjusted to 100°C and left for 5 minutes. Then, a 180° peel test is performed at a peel speed of 300 mm / s in a 100°C environment to determine adhesive strength 1. As will be described later, when a PET substrate is attached to sample 10 composed of a single pressure-sensitive adhesive layer, the PET substrate may be attached in the same manner as above.

[0015] Next, a procedure for measuring adhesive strength 1 when sample 10 is composed of a single adhesive layer will be described. The sample 10 is attached to a SUS plate 20 with a release sheet attached to the rear side thereof, and is then cured in this state in an environment of 100° C. for 3 days. After curing, the release sheet on the back side is removed, and then, as shown in Figure 3, a PET substrate 21 is attached to the back side of sample 10. Sample 10, with PET substrate 21 attached, is placed in a heating furnace adjusted to 110°C for 5 minutes and baked. After baking, the sample is placed in a thermostatic chamber adjusted to 100°C and left for 5 minutes, and then a 180° peel test is performed in a 100°C environment at a peel speed of 300 mm / s, whereby adhesive strength 1 can be determined.

[0016] <Adhesive strength after curing for one day at 23°C> The anticorrosion adhesive tape of the present invention preferably has an adhesive strength (hereinafter also referred to as "adhesive strength 2") of 20 N / 25 mm or more after curing for one day in a 23°C environment, more preferably 25 N / 25 mm or more, and even more preferably 30 N / 25 mm or more. When adhesive strength 2 is equal to or greater than the above lower limit, it can be said that excellent adhesive strength is exhibited even in a high-temperature environment. Furthermore, adhesive strength 2 is not particularly limited, but is preferably 70 N / 25 mm or less, more preferably 60 N / 25 mm or less, and even more preferably 55 N / 25 mm or less. Measurement of adhesive strength 2 may be carried out in the same manner as the measurement method of adhesive strength 1 described above, except that the curing is carried out in an environment of 23°C and 50% RH, and the sample is removed from the heating furnace adjusted to 110°C and left in an environment of 23°C and 50% RH until it returns to 23°C, and then a 180° peel test is carried out in an environment of 23°C and 50% RH.

[0017] <Adhesive layer> (adhesive) The pressure-sensitive adhesive layer is preferably formed from a pressure-sensitive adhesive. The type of pressure-sensitive adhesive is not particularly limited, but examples include acrylic pressure-sensitive adhesives, rubber pressure-sensitive adhesives, urethane pressure-sensitive adhesives, and silicone pressure-sensitive adhesives. These may be used alone or in combination. Among these, the pressure-sensitive adhesive layer is preferably formed from an acrylic pressure-sensitive adhesive.

[0018] (acrylic adhesive) The acrylic pressure-sensitive adhesive may be, for example, a pressure-sensitive adhesive containing an acrylic polymer obtained by polymerizing a polymerizable monomer containing a (meth)acrylic acid alkyl ester monomer (A). In this specification, the term "(meth)acrylic acid alkyl ester" refers to a concept including both acrylic acid alkyl ester and methacrylic acid alkyl ester, and the same applies to other similar terms. Furthermore, the term "polymerizable monomer" refers to a concept that can include not only compounds having no repeating units, but also compounds that copolymerize with the (meth)acrylic acid alkyl ester-based monomer (A), such as the olefin polymer (C) described below, which monomer itself has repeating units.

[0019] ((Meth)acrylic acid alkyl ester monomer (A)) The (meth)acrylic acid alkyl ester monomer (A) is an ester of (meth)acrylic acid and an aliphatic alcohol, and is preferably an alkyl ester derived from an aliphatic alcohol in which the number of carbon atoms in the alkyl group of the aliphatic alcohol is preferably 2 to 14, more preferably 4 to 10. When the number of carbon atoms in the alkyl group is within this range, it is easy to increase adhesive strength, and it is also easy to adjust the storage modulus at 23°C of the pressure-sensitive adhesive described below to a predetermined range.

[0020] Specific examples of the (meth)acrylic acid alkyl ester monomer (A) include ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, and tetradecyl (meth)acrylate. Among these, n-butyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and n-octyl (meth)acrylate are preferred, and n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, or a combination thereof is more preferred. Among these, it is even more preferred to use at least one of n-butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate. By using these, the adhesiveness of the adhesive can be appropriately controlled, and the workability when applying the adhesive tape can be improved. The (meth)acrylic acid alkyl ester-based monomer (A) is preferably an acrylic acid alkyl ester. The (meth)acrylic acid alkyl ester-based monomer (A) may be used alone or in combination of two or more kinds.

[0021] The structural unit derived from the (meth)acrylic acid alkyl ester monomer (A) constitutes the main component of the pressure-sensitive adhesive layer, and its content is generally 30% by mass or more, preferably 50% by mass or more, and more preferably 70% by mass or more, based on the total amount of the pressure-sensitive adhesive layer. Increasing the content of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A) thus facilitates imparting the desired adhesive strength to the pressure-sensitive adhesive layer. Furthermore, the content of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A) is, for example, 97% by mass or less, preferably 95% by mass or less, and more preferably 90% by mass or less, in order to contain a certain amount or more of other components. The content of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A) in the pressure-sensitive adhesive layer is substantially the same as the content of the (meth)acrylic acid alkyl ester monomer (A) in the pressure-sensitive adhesive composition described below, and can be expressed interchangeably. The same applies to components other than component (A), such as components (B) and (C) described below.

[0022] (Polar Group-Containing Vinyl Monomer (B)) The polymerizable monomer preferably contains a polar group-containing vinyl monomer (B) in addition to the (meth)acrylic acid alkyl ester monomer (A). The polar group-containing vinyl monomer (B) has a polar group and a vinyl group. Use of the polar group-containing monomer (B) makes it easier to improve adhesive strength to an adherend. Examples of the polar group-containing vinyl monomer (B) include carboxylic acid vinyl esters such as vinyl acetate, carboxylic acids containing a vinyl group such as (meth)acrylic acid and itaconic acid, and their anhydrides, vinyl monomers having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone-modified (meth)acrylate, polyoxyethylene (meth)acrylate, and polyoxypropylene (meth)acrylate, and nitrogen-containing vinyl monomers such as (meth)acrylonitrile, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinyllaurolactam, (meth)acryloylmorpholine, (meth)acrylamide, dimethyl(meth)acrylamide, N-methylol(meth)acrylamide, N-butoxymethyl(meth)acrylamide, and dimethylaminomethyl (meth)acrylate. Among these, (meth)acrylic acid, itaconic acid, and other vinyl group-containing carboxylic acids and their anhydrides are preferred, (meth)acrylic acid is more preferred, and among these, acrylic acid is even more preferred from the viewpoint of making it easier to maintain a certain level of adhesive strength retention. These polar group-containing vinyl monomers (B) may be used alone or in combination of two or more.

[0023] When a polar group-containing vinyl monomer (B) is used, the content of the structural units derived from the polar group-containing vinyl monomer (B) in the pressure-sensitive adhesive layer is preferably 1 to 15 parts by mass, more preferably 2 to 12 parts by mass, and even more preferably 3 to 10 parts by mass, per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A). By setting the content of the polar group-containing vinyl monomer (B) within this range, the adhesive strength of the pressure-sensitive adhesive tape can be easily improved.

[0024] (olefin polymer (C)) The polymerizable monomer preferably further contains an olefin polymer (C) having a polymerizable bond at one end. Use of such an olefin polymer (C) makes it easier to improve the adhesive strength of the pressure-sensitive adhesive tape. The polymerizable bond means an unsaturated carbon-carbon bond that can be polymerized with a polymerizable monomer, and examples thereof include an unsaturated double bond, and preferably a (meth)acryloyl group. The olefin polymer (C) may be a polyolefin having a (meth)acryloyl group at one end. The polyolefin is a polymer of an aliphatic hydrocarbon compound having a double bond, such as ethylene, propylene, butane, butadiene, or isoprene, or a hydrogenated product thereof.

[0025] Examples of polyolefins having a (meth)acryloyl group at one end include polyethylene having a (meth)acryloyl group at one end, which is prepared by reacting polyethylene having an epoxy group at one end with (meth)acrylic acid. Also included are polybutadienes having a (meth)acryloyl group at one end or hydrogenated products thereof, such as "L-1253" manufactured by Kuraray Co., Ltd.

[0026] The olefin polymer (C) has a number average molecular weight of preferably 500 to 20000, more preferably 1000 to 10000. The number average molecular weight may be measured by gel permeation chromatography (GPC) and calculated using a calibration curve of standard polystyrene. Furthermore, the content of the structural units derived from the olefin polymer (C) in the pressure-sensitive adhesive layer is preferably 1 to 15 parts by mass, more preferably 2 to 12 parts by mass, and even more preferably 3 to 10 parts by mass, per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A).

[0027] (Crosslinking agent (D)) The polymerizable monomer preferably further contains a crosslinking agent. Examples of the crosslinking agent include a polyfunctional monomer having two or more vinyl groups, and preferably a polyfunctional (meth)acrylate having two or more (meth)acryloyl groups. Use of a polyfunctional monomer makes it easier to adjust the adhesive strength of the pressure-sensitive adhesive layer to an appropriate range. The polyfunctional (meth)acrylate is not particularly limited, and examples thereof include hexanediol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, ethoxylated trimethylolpropane triacrylate, proxilated trimethylolpropane triacrylate, proxilated glyceryl triacrylate, neopentyl glycol adipate diacrylate, and the like, as well as polymers such as polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and liquid hydrogenated 1,2-polybutadiene di(meth)acrylate. Among these polyfunctional (meth)acrylates, polymers are preferred, and liquid hydrogenated 1,2-polybutadiene diacrylate is more preferred. Commercially available liquid hydrogenated 1,2-polybutadiene diacrylates include "TEAI-1000" manufactured by Nippon Soda Co., Ltd. The content of the crosslinking agent-derived structural units in the pressure-sensitive adhesive layer may be, for example, 2 parts by mass or less, preferably 0.8 parts by mass or less, more preferably 0.3 parts by mass or less, and even more preferably 0.1 parts by mass or less, per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A). The content of the crosslinking agent-derived structural units in the pressure-sensitive adhesive layer is preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and even more preferably 0.015 parts by mass or more, per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A). When the content of the crosslinking agent-derived structural units is within the above range, the gel fraction can be adjusted to a desired range, and it becomes easier to adjust the adhesive strength retention rate to a certain level or higher. The content of structural units derived from the crosslinking agent in the adhesive layer may be, for example, 0.01% by mass or more and 0.8% by mass or less, based on the total amount of the adhesive layer, preferably 0.01% by mass or more and 0.5% by mass or less, more preferably 0.02% by mass or more and 0.2% by mass or less, and even more preferably 0.03% by mass or more and 0.1% by mass or less.

[0028] (Polymerization initiator) The acrylic adhesive preferably contains a polymerization initiator. Examples of the polymerization initiator include benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin butyl ether, acetophenone compounds such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 4-(1-t-butyldioxy-1-methylethyl)acetophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1, 2-methylanthraquinone, 2-amylanthraquinone, Examples of the compound include anthraquinone compounds such as 2-t-butylanthraquinone and 1-chloroanthraquinone, xanthone compounds such as xanthone, thioxanthone, 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone and 2-chlorothioxanthone, ketal compounds such as acetophenone dimethyl ketal and benzyl dimethyl ketal, benzophenone compounds such as benzophenone, 4-(1-t-butyldioxy-1-methylethyl)benzophenone and 3,3',4,4'-tetrakis(t-butyldioxycarbonyl)benzophenone, and acylphosphine oxide compounds. The content of the polymerization initiator in the acrylic pressure-sensitive adhesive is preferably 0.05 to 0.8 parts by mass, more preferably 0.1 to 0.6 parts by mass, and even more preferably 0.15 to 0.5 parts by mass, per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A). When the content of the polymerization initiator is within the above-mentioned range, it becomes easier to adjust the gel fraction within the desired range. Therefore, by keeping the content of the polymerization initiator within the above-mentioned range, it becomes easier to maintain an adhesive strength retention rate at a certain level or higher, and peeling can be made less likely even in high-temperature environments. The content of the polymerization initiator may be, for example, 0.01 to 1 mass % based on the total amount of the pressure-sensitive adhesive layer, preferably 0.02 to 0.8 mass %, more preferably 0.03 to 0.6 mass %, and even more preferably 0.05 to 0.5 mass %.

[0029] (tackifying resin) The acrylic pressure-sensitive adhesive may contain a tackifying resin from the viewpoint of improving adhesive strength. As the tackifying resin, a tackifying resin with low polymerization inhibition property such as hydrogenated terpene resin, hydrogenated rosin, disproportionated rosin resin, petroleum resin, etc. is preferable. Among these, hydrogenated tackifying resins are preferable because tackifying resins with many double bonds inhibit the polymerization reaction, and hydrogenated petroleum resins are particularly preferable. From the viewpoint of improving the cohesive strength and adhesive strength of the PSA, the softening point of the tackifier resin may be about 95° C. or higher, and preferably includes one that is 120° C. or higher. Furthermore, from the viewpoint of improving the adhesiveness to the adherend, for example, one having a softening point of 95° C. or higher but lower than 120° C. may be used in combination with one having a softening point of 120° C. or higher but 150° C. or lower. The softening point may be measured by the ring and ball method specified in JIS K2207. The content of the tackifier resin in the acrylic pressure-sensitive adhesive is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably less than 5 parts by mass, per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A). By setting the content of the tackifier resin to the above upper limit or less, it becomes easier to adjust the gel fraction within a desired range, and peeling can be made difficult even in high-temperature environments. Furthermore, the acrylic pressure-sensitive adhesive does not need to contain a tackifier resin. Therefore, the content of the tackifier resin may be 0% by mass or more. When a tackifier resin is not contained, it becomes easier to adjust the gel fraction within a desired range, and peeling can be made difficult even in high-temperature environments, compared to when a tackifier resin is contained. However, when a tackifier resin is contained, it is preferable that the content be at least a certain amount from the viewpoint of improving adhesive strength. Specifically, the content is, for example, at least 0.1 parts by mass, preferably at least 1 part by mass, and more preferably at least 2 parts by mass, per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A).

[0030] (Other ingredients) The acrylic adhesive used in the adhesive layer may contain, in addition to the components described above, various additives conventionally used in adhesives, such as fine particles, plasticizers, softeners, pigments, dyes, dispersants, thickeners, and flame retardants.

[0031] (rubber adhesive) The rubber-based pressure-sensitive adhesive contains a rubber component and a tackifying resin, and it is preferable to use a styrene-isoprene block copolymer as the rubber component. The styrene-isoprene block copolymer preferably has a diblock ratio of 25 to 70% by mass, more preferably 30 to 65% by mass, and even more preferably 45 to 60% by weight. Here, diblock refers to a diblock composed of styrene and isoprene. By setting the diblock ratio within the above range, it becomes easier to increase adhesive strength. In addition to diblocks, styrene-isoprene block copolymers also include those having three or more blocks, such as triblocks composed of styrene, isoprene, and styrene blocks.

[0032] The amount of styrene in the styrene-isoprene block copolymer is not particularly limited, but is preferably 14 to 24% by mass, more preferably 15 to 18% by mass. If the amount of styrene is 14% by mass or more, the adhesive tends to have high cohesive strength. If the amount of styrene is 24% by mass or less, the cohesive strength becomes moderate and adhesive strength is easily exerted. The molecular weight of the styrene-isoprene block copolymer is not particularly limited, but is preferably a mass average molecular weight of 100,000 to 400,000, more preferably 150,000 to 250,000. The mass average molecular weight here refers to a molecular weight measured as polystyrene equivalent by GPC (gel permeation chromatography).

[0033] Various tackifying resins can be used for rubber-based adhesives, but petroleum-based resins, terpene resins, and coumarone resins are preferred. While one tackifying resin may be used alone or in combination with two or more, it is preferred to use a petroleum-based resin in combination with at least one selected from terpene resins and coumarone resins. Such a combination of tackifying resins facilitates improved adhesive strength. The rubber-based pressure-sensitive adhesive may contain fine particles, a sacrificial anticorrosive metal, a conductive material, a softener, an antioxidant, a filler, and the like, as required.

[0034] (urethane adhesive) The urethane-based adhesive is not particularly limited, and examples thereof include urethane resins obtained by reacting at least a polyol with a polyisocyanate compound. Examples of the polyol include polyether polyol, polyester polyol, polycarbonate polyol, and polycaprolactone polyol. Examples of the polyisocyanate compound include diphenylmethane diisocyanate, tolylene diisocyanate, and hexamethylene diisocyanate. These urethane adhesives may be used alone or in combination of two or more. The urethane-based adhesive may be a urethane resin obtained by reacting a polyurethane polyol with a polyfunctional isocyanate curing agent. Examples of the polyurethane polyol include a reaction product of the above-mentioned polyol with a polyisocyanate compound, or a reaction product of a polyol, a polyisocyanate compound, and a chain extender such as a diamine. The polyfunctional isocyanate curing agent may be any compound having two or more isocyanate groups, and the above-mentioned isocyanate compounds can be used. The urethane-based adhesive may contain the above-mentioned fine particles in addition to the urethane resin, and may also contain a tackifying resin, a sacrificial anticorrosive metal, a conductive material, a softener, an antioxidant, a filler, etc., as necessary.

[0035] (Silicone adhesive) Examples of silicone-based adhesives include addition reaction type, peroxide curing type, and condensation reaction type silicone-based adhesives. Among these, addition reaction type silicone-based adhesives are preferably used from the viewpoint of being able to cure at low temperature in a short time. Note that addition reaction type silicone-based adhesives cure when the adhesive layer is formed. When an addition reaction type silicone-based adhesive is used as the silicone-based adhesive, the silicone-based adhesive may contain a catalyst such as a platinum catalyst. The silicone adhesive may contain fine particles, and may also contain a crosslinking agent and various additives for controlling adhesive strength.

[0036] (a metal with a lower potential than iron) The adhesive layer preferably contains a metal having a lower potential than iron. By containing a metal having a lower potential than iron (hereinafter also referred to as "sacrificial corrosion protection metal"), sacrificial corrosion protection against iron is imparted, thereby improving the corrosion protection of the adhesive tape. The sacrificial corrosion protection metal is dispersed in the adhesive that constitutes the adhesive layer.

[0037] Examples of sacrificial corrosion protection metals include cadmium, chromium, zinc, manganese, and aluminum. Of these, zinc and aluminum are preferred, with zinc being particularly preferred. The use of zinc provides excellent sacrificial corrosion protection.

[0038] The sacrificial corrosion protection metal may be dispersed in the pressure-sensitive adhesive as a filler in any form, such as a particle form, a scale form, a spindle form, etc., but is preferably in a particle form. By making the sacrificial corrosion protection metal in a particle form, it becomes easier to disperse in the pressure-sensitive adhesive layer without substantially reducing the adhesiveness of the pressure-sensitive adhesive layer. In this specification, the particulate shape refers to a shape in which the ratio of the length in the major axis direction to the length in the minor axis direction (aspect ratio) is small, for example, an aspect ratio of 3 or less, preferably 2 or less. The particle shape is not particularly limited, and may be spherical or may be an amorphous shape such as powder. The particle size of the above particulate metal is, for example, 1 to 500 μm, preferably 1 to 200 μm. In this specification, the particle size refers to the average particle size measured by laser diffraction.

[0039] When the pressure-sensitive adhesive layer contains a sacrificial metal, the content of the sacrificial metal in the pressure-sensitive adhesive layer is, for example, 0.5 to 30 mass%, preferably 1 to 20 mass%, and more preferably 2 to 15 mass%, based on the total amount of the pressure-sensitive adhesive layer. When the content of the sacrificial metal is equal to or greater than these lower limits, the sacrificial protection is enhanced, thereby improving corrosion prevention performance. When the content is equal to or less than these upper limits, the adhesive strength is easily increased.

[0040] In a preferred embodiment, the pressure-sensitive adhesive layer does not contain a sacrificial anticorrosive metal. When the pressure-sensitive adhesive layer does not contain a sacrificial anticorrosive metal, the pressure-sensitive adhesive tape maintains a high adhesive strength compared to when the pressure-sensitive adhesive layer contains a sacrificial anticorrosive metal, making the pressure-sensitive adhesive tape less likely to peel from the adherend, thereby blocking water and oxygen and improving corrosion prevention.

[0041] (Conductive materials) The pressure-sensitive adhesive layer may contain a conductive material other than the sacrificial protection metal. When the pressure-sensitive adhesive layer contains a sacrificial protection metal, it preferably contains a conductive material. When the pressure-sensitive adhesive layer contains a conductive material, electrons released when the sacrificial protection metal is ionized can be more easily transferred to the adherend, and the sacrificial protection properties can be more easily improved. The conductive material may be one or more selected from carbon-based materials, metal-based materials, metal oxide-based materials, ionic polymers, and conductive polymers. Examples of carbon-based materials include carbon black, graphite, graphene, carbon nanotubes, and acetylene black. Examples of metal-based materials include iron, or metals with a more noble potential than iron, such as gold, silver, copper, nickel, or alloys containing these metals. Examples of metal oxide-based materials include indium tin oxide (ITO), antimony trioxide (ATO), fluorine-doped tin oxide (FTO), and zinc oxide. Examples of conductive polymers include polyacetylene, polypyrrole, PEDOT (polyethylenedioxythiophene), PEDOT / PSS (a composite of polyethylenedioxythiophene and polystyrene sulfonic acid), polythiophene, polyaniline, poly(p-phenylene), polyfluorene, polycarbazole, polysilane, or derivatives thereof. Examples of ionic polymers include sodium polyacrylate and potassium polyacrylate. The conductive material may be used alone or in combination of two or more. Among the above, carbon-based materials are preferred as the conductive material, and carbon nanotubes are more preferred.

[0042] (carbon nanotubes) As described above, the pressure-sensitive adhesive layer may contain carbon nanotubes as a conductive material. The inclusion of carbon nanotubes improves the sacrificial corrosion protection of the pressure-sensitive adhesive layer, while maintaining high adhesive strength and transparency. This makes it easier to obtain a pressure-sensitive adhesive tape that combines high adhesive strength, sacrificial corrosion protection, and high transparency. This is presumably because, although carbon nanotubes are a conductive material, a smaller amount is required to exhibit a certain level of sacrificial corrosion protection compared to other types of conductive materials, resulting in a smaller degree of decrease in adhesive strength.

[0043] Carbon nanotubes are tubular materials made from carbon. They have excellent electrical properties, and when combined with resins, they can be used to form highly conductive sheets. Carbon nanotubes are made of graphite sheets with a hexagonal mesh of carbon atoms rolled into a cylindrical shape. Nanotubes rolled in one layer are called single-wall carbon nanotubes, while nanotubes rolled in multiple layers are called multi-wall carbon nanotubes. The type of carbon nanotube is not particularly limited, and may be any of single-walled carbon nanotubes, multi-walled carbon nanotubes, and mixtures thereof containing any ratio. Carbon nanotubes manufactured by various methods such as arc discharge, laser evaporation, and chemical vapor deposition (CVD) can also be used.

[0044] The carbon nanotubes preferably have an average diameter of 1 to 100 nm, more preferably 2 to 15 nm. The carbon nanotubes preferably have an average length of 0.1 to 1,000 μm, more preferably 10 to 500 μm. The carbon nanotubes preferably have an aspect ratio (average length / average diameter) of 10 to 100,000, more preferably 500 to 30,000. The diameter of a carbon nanotube refers to the outer diameter in the case of a single-walled carbon nanotube, and the outer diameter of the outermost tube in the case of a multi-walled carbon nanotube. The diameter and length of a carbon nanotube can be measured, for example, from an image obtained by observation with a transmission electron microscope (TEM), and the average diameter and average length can be calculated by taking the arithmetic mean of any 50 nanotubes.

[0045] From the viewpoints of the sacrificial corrosion protection and adhesive strength of the pressure-sensitive adhesive layer, and the transparency of the pressure-sensitive adhesive tape, the content of the conductive material in the pressure-sensitive adhesive layer is preferably 0.001 to 10 mass%, more preferably 0.002 to 5 mass%, and even more preferably 0.003 to 3 mass%, based on the total amount of the pressure-sensitive adhesive layer. The content of the conductive material in the pressure-sensitive adhesive layer may be, for example, 0.001 to 0.7 mass%, preferably 0.0015 to 0.05 mass%, more preferably 0.002 to 0.045 mass%, and even more preferably 0.003 to 0.045 mass%, based on the total amount of the pressure-sensitive adhesive layer.

[0046] When the conductive material is carbon nanotubes, the content of the carbon nanotubes in the adhesive layer is preferably 0.0005 to 0.7 mass %, more preferably 0.002 to 0.05 mass %, and even more preferably 0.003 to 0.045 mass %, based on the total mass of the adhesive layer. When the carbon nanotube content is equal to or greater than these lower limits, the sacrificial corrosion protection is likely to be enhanced, whereas when the carbon nanotube content is equal to or less than these upper limits, the adhesive strength is likely to be improved and the transparency of the adhesive tape can be ensured.

[0047] (Acrylic pressure-sensitive adhesive and method for producing pressure-sensitive adhesive layer) The acrylic pressure-sensitive adhesive can be obtained by irradiating a pressure-sensitive adhesive composition containing the above-mentioned polymerizable monomer, and optionally a polymerization initiator, a sacrificial corrosion-protective metal, and a conductive material, with light to polymerize the polymerizable monomer. The pressure-sensitive adhesive composition may also optionally contain the above-mentioned tackifier resin and at least one other component. More specifically, first, a polymerizable monomer, a polymerization initiator which is blended as needed, a sacrificial anticorrosive metal and a conductive material, a tackifier resin which is further blended as needed, and other components are placed in a reaction vessel such as a glass vessel and mixed to obtain a pressure-sensitive adhesive composition. Next, in order to remove dissolved oxygen in the pressure-sensitive adhesive composition, an inert gas such as nitrogen gas is generally supplied to purge the oxygen. Then, the pressure-sensitive adhesive composition is applied onto a release sheet, or onto a support such as a resin film, woven fabric, or nonwoven fabric, and then irradiated with light to polymerize the polymerizable monomer, thereby obtaining a pressure-sensitive adhesive layer. The steps from the application or impregnation of the pressure-sensitive adhesive composition to the light irradiation are preferably carried out in an inert gas atmosphere or in a state where oxygen is blocked by a film or the like. In the present production method, the pressure-sensitive adhesive composition obtained by mixing the components may be pre-polymerized before being applied to a release sheet, a support, or the like, in order to increase the viscosity. In the above description, the polymerizable monomer is polymerized by irradiating it with light, but the polymerizable monomer may be polymerized by a method other than irradiating it with light.

[0048] (storage modulus) The pressure-sensitive adhesive layer preferably has a storage modulus of 140 kPa or more in a 100°C environment, more preferably 142 kPa or more, and even more preferably 145 kPa or more. When the storage modulus in a 100°C environment is equal to or greater than the above-mentioned lower limit, it becomes easier to maintain a certain level of adhesive strength retention. The storage modulus in a 100°C environment is not particularly limited, but is, for example, 250 kPa or less, preferably 200 kPa or less. By keeping the storage modulus in a 100°C environment within the above range, the pressure-sensitive adhesive layer can suppress a decrease in adhesive strength.

[0049] (gel fraction) The gel fraction of the pressure-sensitive adhesive layer is preferably 40 to 80% by mass, more preferably 45 to 77% by mass, and even more preferably 55 to 75% by mass. By setting the gel fraction within the above range, the anticorrosion pressure-sensitive adhesive tape tends to maintain excellent peel strength even when exposed to a high-temperature environment. The gel fraction can be adjusted by the blending of the above-mentioned crosslinking agent or polymerization initiator, or by the manufacturing conditions of the pressure-sensitive adhesive layer (for example, the light irradiation conditions in the case of photocuring). An example of a formulation that can adjust the gel fraction of the pressure-sensitive adhesive layer to within the above range is one in which the pressure-sensitive adhesive layer contains 0.05 to 0.5 mass% of a polymerization initiator, based on the total amount of the pressure-sensitive adhesive layer, contains 0 to 5 mass% of a tackifying resin, based on the total amount of the pressure-sensitive adhesive layer, and contains 0.01 to 0.2 mass% of a structural unit derived from a crosslinking agent, based on the total amount of the pressure-sensitive adhesive layer.

[0050] (Thickness) The thickness of the adhesive layer is preferably 100 μm or more, more preferably 200 μm or more, even more preferably 300 μm or more, and even more preferably 500 μm or more. By making the thickness equal to or greater than the above-mentioned lower limit, the self-repairing ability and other properties can be enhanced, improving the corrosion resistance of the adhesive tape, and the adhesive strength can also be easily increased. Furthermore, the thickness of the adhesive layer is preferably 2000 μm or less, more preferably 1500 μm or less, and even more preferably 1200 μm or less. By making the thickness of the adhesive layer equal to or less than the above-mentioned upper limit, the effect of improving corrosion resistance according to the thickness can be obtained.

[0051] <Configuration of anti-corrosion adhesive tape> The anticorrosion adhesive tape of the present invention may be composed of a single adhesive layer, but as shown in Fig. 1, the anticorrosion adhesive tape 10 is preferably a single-sided adhesive tape having a substrate 12 and an adhesive layer 11 provided on one side of the substrate 12. This allows the adhesive layer 11 to be protected by the substrate 12. The anticorrosion adhesive tape is used by adhering the surface 11A of the adhesive layer 11 to an adherend as an adhesive surface. Although not shown, the anticorrosive adhesive tape may be a double-sided adhesive tape having a substrate and adhesive layers provided on both sides of the substrate.

[0052] (base material) The substrate constituting the anticorrosion adhesive tape of the present invention is not particularly limited as long as it has heat resistance, but a resin film is preferred. Examples of resins that can be used to form the resin film include acrylic resins, fluorine-based resins, polycarbonate resins, polyvinyl chloride resins, AES resins, and ASA resins. These resins can be used alone or in combination of two or more. The resin is preferably at least one selected from the group consisting of polyvinyl chloride resins, acrylic resins, and fluorine-based resins. Therefore, the resin film is preferably at least one of polyvinyl chloride resin films, acrylic resin films, and fluorine-based resin films, with polyvinyl chloride resin films being more preferred. The resin film used as the substrate may be single-layered or multi-layered. In the case of a multi-layered structure, only resin films of the same type may be laminated, or two or more resin films may be laminated.

[0053] <Applications and usage> The uses of the anticorrosion pressure-sensitive adhesive tape of the present invention are not particularly limited, but because it is difficult to peel even in high-temperature environments, it is preferably used for repairing structures such as steam pipes and steel materials such as H-beams installed inside factories, etc., and more preferably for repairing steam pipes installed inside factories, etc. Specifically, when at least one of corrosion such as rust and damage occurs on a structure, by applying the tape to the corroded or damaged area, it is possible to suppress the progression of corrosion or damage, or corrosion of the structure from the damaged area. [Example]

[0054] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0055] [Evaluation method] In the examples and comparative examples, the anticorrosion adhesive tapes were evaluated by the following evaluation methods.

[0056] <High-temperature storage modulus at 100°C> The storage modulus at 100°C of the adhesive layer of the adhesive tape obtained in each of the Examples and Comparative Examples was calculated by measuring the dynamic viscoelasticity spectrum using a dynamic viscoelasticity measuring device (manufactured by IT Measurement & Control Co., Ltd., product name "DVA-200") under the following conditions: shear mode: 10 Hz, strain: 0.1%, temperature range: -50°C to 150°C, and heating rate: 10°C / min.

[0057] <Gel fraction> W1 (g) was collected from the adhesive layer of the anticorrosion adhesive tape, and the collected adhesive component was immersed in ethyl acetate at 23°C for 24 hours. The insoluble matter was filtered through a 200-mesh wire netting. The residue on the wire netting was dried by heating at 110°C, and the weight W2 (g) of the resulting dried residue was measured. The gel fraction (degree of cross-linking) was calculated using the following formula. Gel fraction (mass%) = 100 × W2 / W1

[0058] <180° adhesive strength after curing> The adhesive strength was measured after curing for one day in an environment at 23° C. and after curing for three days in an environment at 100° C. The measurement method was as follows.

[0059] (Adhesive strength after curing for 1 day at 23°C) As shown in FIG. 2, a 15 mm x 100 mm sample 10 was taken from the adhesive tape prepared in each Example and Comparative Example. The release sheet on the side opposite to the UV-irradiated side was peeled off, and the adhesive layer (sample 10) was attached to a SUS plate (SS400) 20. A 2 kg roller was rolled back and forth on sample 10 twice, and then cured for one day in a 23°C environment. After curing, the other release sheet laminated on the adhesive layer was peeled off, and a PET substrate (50 μm) 21 that had been primer-treated with NK350 manufactured by Nippon Shokubai Co., Ltd. was attached to sample 10 (adhesive layer) as shown in FIG. 3. A 2 kg roller was rolled back and forth on the PET substrate 21 twice. Then, sample 10, with the PET substrate 21 attached, was placed in a heating oven adjusted to 110°C for 5 minutes and baked. After being removed from the heating oven, the sample was left until the temperature returned to 23°C. After the sample temperature returned to 23°C, a 180° peel test was carried out on the sample at a peel speed of 300 mm / s in an environment of 23°C and 50% RH. The measurement was carried out over a 15 mm width, but the adhesive strength value was converted to a value over a 25 mm width.

[0060] (Adhesive strength after curing for 3 days in a 100°C environment) The adhesive strength after curing for 3 days in a 100°C environment was measured in the same manner as above, except that the temperature and period during curing were changed to 100°C and 3 days, respectively, and that after removing from the heating furnace, the sample was placed in a thermostatic chamber adjusted to 100°C and left for 5 minutes, and then a 180° peel test was performed in a 100°C environment.

[0061] <Adhesion maintenance rate> The adhesive strength retention rate was calculated using the following formula. Adhesive strength retention rate (%) = (adhesive strength after curing for 3 days at 100°C / adhesive strength after curing for 1 day at 23°C) x 100

[0062] <Practical evaluation of peeling> A corrosion-preventive adhesive tape (25 mm wide, 100 mm long) from each example and comparative example was attached to a steam pipe at 100°C to prepare a peeling evaluation sample. Water was sprayed for 5 minutes at a water pressure of 8 MPa toward the longitudinal end side of the corrosion-preventive adhesive tape from a spraying position diagonally above the corrosion-preventive adhesive tape in the peeling evaluation sample. The water spraying position (spraying position) was set so that the angle between the pipe and a line connecting the spraying position and the center of the end of the corrosion-preventive adhesive tape was 30°, and the position was directly above a point 5 cm horizontally away from the center of the end of the corrosion-preventive adhesive tape. The distance that the anticorrosive adhesive tape peeled off after the water spraying was measured and evaluated according to the following criteria. ◎ Peeling distance is 0mm or more and less than 15mm ○ Peeling distance is 15mm or more but less than 25mm × Peeling distance is 25mm or more

[0063] [Ingredients used] In each of the examples and comparative examples, the following materials were used.

[0064] <Adhesive layer> 2-Ethylhexyl acrylate n-Butyl acrylate Acrylic acid Olefin polymer: Product name "L-1253", manufactured by Kuraray Co., Ltd., hydrogenated polybutadiene with a (meth)acryloyl group at one end Tackifying resin 1: Product name "Alcon P100", manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 100°C Tackifying resin 2: Product name "Alcon P140", manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 140°C Thickener: Product name "AEROSIL 200PE", manufactured by Nippon Aerosil Co., Ltd. Metal with a lower potential than iron: Zinc particles, manufactured by Toho Zinc Co., Ltd., product name "AN-200", average particle size: 40 μm Conductive material: Carbon nanotubes (CNTs), manufactured by JEIO, product name "JENOTUBE8A", average diameter 6-9 nm, average length 100-200 μm Crosslinking agent: Product name "TEAI-1000", manufactured by Nippon Soda Co., Ltd. Polymerization initiator: 2,2-dimethoxy-2-phenylacetophenone

[0065] [Examples 1 to 7, Comparative Examples 1 to 5] A pressure-sensitive adhesive composition was prepared according to the formulation shown in Table 1. Nitrogen was purged into this pressure-sensitive adhesive composition to remove dissolved oxygen. Next, a spacer having the same thickness as the pressure-sensitive adhesive layer was placed on the release-treated surface of the release sheet, and the pressure-sensitive adhesive composition was applied to the release-treated surface of the release sheet. Next, another release sheet was placed on top of the applied pressure-sensitive adhesive composition so that the release-treated surface was in contact with the pressure-sensitive adhesive composition. Note that a silicone release-treated PET film (thickness 50 μm) was used as the release sheet. In this state, the ultraviolet irradiation intensity on the release sheet on the coated side was 5 mW / cm 2 The lamp intensity of the chemical lamp was adjusted so that the ultraviolet light was irradiated from one side for 15 minutes, thereby obtaining an anticorrosion adhesive tape consisting of a single adhesive layer with release sheets attached to both sides.

[0066] [Table 1]

[0067] As is clear from the above examples, the anticorrosion adhesive tape that meets the requirements of the present invention had an adhesive strength retention rate of a certain level or higher, and was therefore less likely to peel off from the substrate even in high-temperature environments. In contrast, the adhesive strength retention rate of all the pressure-sensitive adhesive tapes produced in the comparative examples did not satisfy a certain standard, and peeling from the adherend occurred in a high-temperature environment. [Explanation of symbols]

[0068] 10 adhesive tape 11 Adhesive layer 12 Base material 20 SUS board 21 Primed PET substrate

Claims

1. An anticorrosion adhesive tape having an adhesive layer, An anticorrosion pressure-sensitive adhesive tape, wherein the pressure-sensitive adhesive layer has an adhesive strength retention rate at 100°C of 50% or more as determined by the following formula (1): Adhesive strength retention rate (%) = Adhesive strength (N / 25 mm) of the anticorrosion adhesive tape after curing for 3 days in a 100°C environment / Adhesive strength (N / 25 mm) of the anticorrosion adhesive tape after curing for 1 day in a 23°C environment × 100 (1)

2. The anticorrosion adhesive tape according to claim 1, wherein the adhesive strength of the adhesive layer after the anticorrosion adhesive tape is cured in an environment of 100°C for 3 days is 20 N / 25 mm or more.

3. The corrosion prevention pressure-sensitive adhesive tape according to claim 1 or 2, wherein the pressure-sensitive adhesive layer has a storage modulus of 140 kPa or more in an environment of 100°C.

4. The anticorrosion adhesive tape according to claim 1 or 2, wherein the adhesive layer is formed from an acrylic adhesive.

5. the acrylic pressure-sensitive adhesive contains a structural unit derived from a (meth)acrylic acid alkyl ester monomer, 5. The corrosion-preventing adhesive tape according to claim 4, wherein the acrylic pressure-sensitive adhesive does not contain a tackifier resin, or the acrylic pressure-sensitive adhesive contains a tackifier resin and the content of the tackifier resin is less than 5 parts by mass per 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester-based monomer.

6. The anticorrosion adhesive tape according to claim 1 or 2, wherein the pressure-sensitive adhesive layer has a gel fraction of 40 to 80 mass %.

7. The corrosion-preventing adhesive tape according to claim 1 or 2, wherein the adhesive layer contains zinc.

8. The corrosion-preventing adhesive tape according to claim 1 or 2, wherein the adhesive layer contains a conductive material.

9. The anticorrosion adhesive tape according to claim 1 or 2, wherein the thickness of the adhesive layer is 100 μm or more.

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